import java.util.LinkedList;
import java.util.Queue;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: 62536
 * Date: 2024-02-18
 * Time: 15:10
 */
//队列实现栈，需要两个队列
public class MyStack {
    private Queue<Integer> queue1 ;
    private Queue<Integer> queue2 ;

    public MyStack() {
        queue1 = new LinkedList<>();
        queue2 = new LinkedList<>();
    }

    public void push(int x) {
        if(empty()){
            queue1.offer(x);
            return;
        }
        if(!queue1.isEmpty()){
            queue1.offer(x);
        } else {
            queue2.offer(x);
        }
    }

    public int pop() {
        if(empty()){
            return -1;
        }
        if(!queue1.isEmpty()){
            int size = queue1.size();
            for(int i = 0; i < size-1; i++){
                queue2.offer(queue1.poll());
            }
            return queue1.poll();
        } else {
            int size = queue2.size();
            for(int i = 0; i < size-1; i++){
                queue1.offer(queue2.poll());
            }
            return queue2.poll();
        }
    }

    public int top() {
        if(empty()){
            return -1;
        }
        if(!queue1.isEmpty()){
            int size = queue1.size();
            int tmp = -1;
            for(int i = 0; i < size; i++){
                tmp = queue1.poll();
                queue2.offer(tmp);
            }
            return tmp;
        } else {
            int size = queue2.size();
            int tmp = -1;
            for(int i = 0; i < size; i++){
                tmp = queue2.poll();
                queue1.offer(tmp);
            }
            return tmp;
        }
    }

    public boolean empty() {
        return queue1.isEmpty() && queue2.isEmpty();
    }

}
